Network Sharing problem

i have three pc networked using bridge. One pc connect to the broadband modem and the other two connected to it via 2 NIC. So this Host PC had got three NICs.

The other two pc can 'see' each other with no problem(as weel as sharing files,etc etc), so can the host see the other two. Either of the other two can 'see' the host in 'My Network Places', but cant access the host. Keep saying the host PC is not accessible. NO problem sharing(accessing) the internet.

I thought i have set all the sharing access rights on th Host pc but it still doesnt work. Obviously i must have missed something here.

When i go to newrok connection on the Host pc, under 'LAN or High Speed Internet', i can see it says Local area connection 3. Wonder if the 3 has anything to do with the problem.